Numerous electrical systems demand both DC power and AC power of high availability to run different electrical components. For example, telecommunications systems which require DC power for most electrical components, also require AC power for monitoring and controlling components. For systems like those in the telecommunications area in which both the DC powered and the AC powered electrical equipment are sensitive to voltage fluctuations and faults, and in which an existing DC power source is used, an inverter is often used to create AC power from the existing DC power source. Such an inverter system operating off an existing battery source in Telecom or similar offices is more cost effective than using a separate power source or separate source battery.
In conventional systems such as those described above, the inverter input current received which the DC/DC converter draws from the source is not constant. Instead, the input current has a ripple current on top of the DC current. This ripple current, which, for example, may take the form of 120 Hz ripples on the DC current results from the operation of the inverter circuit block. Specifically, the power train of the inverter creates this ripple effect by drawing a slightly sinusoidal DC current from the DC/DC converter. This ripple effect on the DC output current from the DC/DC converter constitutes input noise to the DC voltage source.
In addition, inverters and the downstream circuits which they power are often sensitive to sharp fluctuations in driving voltage. For example, upon turn-on of downstream components the inverter circuit may see a sharp load increase. The resultant effect on the output DC voltage from the DC/DC converter is a sharp decrease in the output voltage and, therefore, a sharp decrease in input voltage to the inverter. The opposite effect can occur with sharp decreases in the load. In either situation, the sharp voltage fluctuation is detrimental to inverter operation and the driving of downstream circuits.